Undertow is a ranged mass-manipulation power that allows Booker to use a stream of water to pull an enemy closer to him (hold the Vigor button) or to push them away (tap the Vigor button). Undertow can be found in The Factory.
Undertow can also be used as a means of pulling various enemies (if upgraded) into a devil's kiss trap or even a shock jocke trap.
Using Undertow and Shock jockey is also a requirement for unlocking the achievment/trophy Combination Shock.
|Veni Vidi Vigor|
|Max Upgrade Cost||$1449|
If the upgrade has been acquired, and the player is able to use Undertow to grab more than one enemy, it is more ammunition-efficient to go to the side of the enemies directly after they are pulled in front of the player and shoot from the side, elimanting the need for greater accuracy or speed. The idea behind this is that once the enemy being shot at first dies, the enemy directly next to the first one will become the one hit by the bullets, making the system more efficient and keeping all enemies in sight.